Conventionally, there have been methods to raise the efficiency of making a program by visualization using diagrams such as a flow chart, PAD (Program Analysis Diagram), and the like. The flow chart, PAD and the like facilitates the comprehension of a program by illustrating two dimensionally the controlling flow of a conditional branch or iteration loop in the program. However, any data that the program manipulates cannot be visualized.
Real data has been manipulated in spreadsheets, e.g., as commands and formulas are entered in displayed boxes.
On the other hand, a method using icons whereby the icons symbolizing abstract data that a program manipulates or uses in procedures can be displayed visually in order to facilitate the making of the program is described in IEEE software, Vol. 4, No. 1, pp. 29-39 (1987).